[SCAQTony]

Apple's "Monopoly Sentinels" won't let me open it. To wit, “Pinnacle a Sentinel remake” can’t be opened because Apple cannot check it for malicious software." • This software needs to be updated. Contact the developer for more information."

[tunaoftheland]

I had to right-click open twice in a row, back-to-back. I've seen this with other apps downloaded from non-app-store, from time to time. Very non-intuitive but rewards (irrational) persistence. :)

[lagniappe]

Next to the download button are the instructions to overcome this.